On Mon, Nov 18, 2019 at 04:21:39PM -0500, Aaron Conole wrote: > Marcelo Ricardo Leitner <marcelo.leit...@gmail.com> writes: > > > On Fri, Nov 08, 2019 at 04:07:14PM -0500, Aaron Conole wrote: > >> The act_ct TC module shares a common conntrack and NAT infrastructure > >> exposed via netfilter. It's possible that a packet needs both SNAT and > >> DNAT manipulation, due to e.g. tuple collision. Netfilter can support > >> this because it runs through the NAT table twice - once on ingress and > >> again after egress. The act_ct action doesn't have such capability. > >> > >> Like netfilter hook infrastructure, we should run through NAT twice to > >> keep the symmetry. > >> > >> Fixes: b57dc7c13ea9 ("net/sched: Introduce action ct") > >> > >> Signed-off-by: Aaron Conole <acon...@redhat.com> > >> --- > >> net/sched/act_ct.c | 13 ++++++++++++- > >> 1 file changed, 12 insertions(+), 1 deletion(-) > >> > >> diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c > >> index fcc46025e790..f3232a00970f 100644 > >> --- a/net/sched/act_ct.c > >> +++ b/net/sched/act_ct.c > >> @@ -329,6 +329,7 @@ static int tcf_ct_act_nat(struct sk_buff *skb, > >> bool commit) > >> { > >> #if IS_ENABLED(CONFIG_NF_NAT) > >> + int err; > >> enum nf_nat_manip_type maniptype; > >> > >> if (!(ct_action & TCA_CT_ACT_NAT)) > >> @@ -359,7 +360,17 @@ static int tcf_ct_act_nat(struct sk_buff *skb, > >> return NF_ACCEPT; > >> } > >> > >> - return ct_nat_execute(skb, ct, ctinfo, range, maniptype); > >> + err = ct_nat_execute(skb, ct, ctinfo, range, maniptype); > >> + if (err == NF_ACCEPT && > >> + ct->status & IPS_SRC_NAT && ct->status & IPS_DST_NAT) { > >> + if (maniptype == NF_NAT_MANIP_SRC) > >> + maniptype = NF_NAT_MANIP_DST; > >> + else > >> + maniptype = NF_NAT_MANIP_SRC; > >> + > >> + err = ct_nat_execute(skb, ct, ctinfo, range, maniptype); > >> + } > > > > I keep thinking about this and I'm not entirely convinced that this > > shouldn't be simpler. More like: > > > > if (DNAT) > > DNAT > > if (SNAT) > > SNAT > > > > So it always does DNAT before SNAT, similarly to what iptables would > > do on PRE/POSTROUTING chains. > > I can rewrite the whole function, but I wanted to start with the smaller > fix that worked. I also think it needs more testing then (since it's > something of a rewrite of the function). > > I guess it's not too important - do you think it gives any readability > to do it this way? If so, I can respin the patch changing it like you > describe.
I didn't mean a rewrite, but just to never handle SNAT before DNAT. So the fix here would be like: - return ct_nat_execute(skb, ct, ctinfo, range, maniptype); + err = ct_nat_execute(skb, ct, ctinfo, range, maniptype); + if (err == NF_ACCEPT && maniptype == NF_NAT_MANIP_DST && + ct->status & IPS_SRC_NAT && ct->status & IPS_DST_NAT) { + maniptype = NF_NAT_MANIP_SRC; + err = ct_nat_execute(skb, ct, ctinfo, range, maniptype); + } + return err; > >> + return err; > >> #else > >> return NF_ACCEPT; > >> #endif > >> -- > >> 2.21.0 > >> > _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev